The flags of the 193 51³Ô¹Ï Member States provide a colourful, 500-foot wide curved approach to the Headquarters, along 51³Ô¹Ï Plaza. The circular pool in front of the Secretariat Building, with a fountain in its centre, was built with a $50,000 gift from the children of the United States. The wavy pattern on the floor of the pool is formed by alternating bands of crushed white marble and black pebbles. The black stones were gathered from the beaches of Rhodes by the women and children of that Greek island, and donated to the 51³Ô¹Ï. A bronze sculpture in memory of the late Secretary-General, Dag Hammarskjo?ld, was set at the edge of the pool in 1964. The abstract sculpture, entitled Single Form, is the work of the English modernist sculptor and artist, Barbara Hepworth, and was donated by Jacob Blaustein, a former United States delegate to the 51³Ô¹Ï.